David johnson



Unitas Snares PATENT Erica DAVID JOHNSON, or sourn l-IAMPSTEAD, COUNTY OF MIDDLESEX, ENGLAND.

PROCESS OF PREPARING EXPLOSIVES.

SPECIFICATION forming part of Letters Patent No. 376,000, dated January 3, 1888,,

Applicaton filed Juno 8, 1886. Serial No. 204,530. (No specimens.) Patented in'England July 24, 1885, No. 8,951.

To aZZ whom, it may concern.-

Be it known that 1, DAVID JOHNs0N,-a subject of the Queen of Great Britain, residing at South Hampstead, in the county of Middlesex, in England, have invented new and useful Improvements in the Manufacture of Explosives, (for which I have secured Letters Patent in Great Britain, No. 8,951, dated July 24,.

and certain means for making, on a large scale,

spdrting and military powders easy ofignition, but of any required hardness and density for slow combustion and maximum velocity with lowering of trajectory. In my process I use any nitrocellulose compounds of various degrees of nitration, alone or in combination such as trinitro, dinitro, and mononitro cellulose, and those of intermediate nitration, and

also dinitro-cellnlose alone or together with nitro-cellulose compounds of lower degrees of nitration than trinitro-cellulose-via,without trinitro-cellulose, as heretofore. The ordinary gun-cotton now used is an imperfect trinitrocellulose, inasmuch as ittcontains proportions of other nitro-cellulose of lower degrees of nitration,which proportions practically are of a varying quantity, so that it is difficult to obtain commercially two samples alike. Although these variations may be slight, yet in practice I have found by experimentthat they induce marked variable and" sometimes.dangerous effect in the action of the finished product when used in the fire-arm.

\Vhere hcreinafterI speak generally of trinitrocellulosc, it includes what is called ,guucotton.

used as one of the essential constituents of the While I do not in my invention-confine my explosive, either in my invention or by, the processes employed in the preparation of the various heretofore known nitro compdunds, (used for fire-arms,) an element of uncertainty is introduced owing to the difficulty of pie-.

paring commercially a true trinitroc'cllulose. An element of great uncertainty is thus introduced into the explosive,'\vhich,- under cer; tain further slightly-varying conditions-such as manner of loading, pressure in loading, 6

strength of cap, and shape of cartridge-case render it extremely difficult and almost impossible to prepare a powder for the above purposes which shall not, under some of these varying conditions, explode with abnormal 6 suddenness, and thus give rise to an abnormal strain upon theweapon, sometimes even to bursting force, as has often been the case in practice.

Anelemeiit of dangerhas becn'discovered in powders containing trinitro-cellulose in important quantities, as in powders made from nitrocellulose now in the market, in regard to the amount of moisture contained in such There appears in this respect to be powders. only one condition of maximum utility and of safety, and that is when the powder is in its average normal or air-dry state. NVhen, however, such powder is subjectedto extremely moist conditions, and consequently takes up 80 more moisture than its average normal or air dry condition would demand, then there is objectionable hang fire. This moisture can be driven off, and when the powder has regained its average normal air-dry state, then'it regains its usefulness; but it (as has been found the case in practice) the powder has been subjected to awarmt'h or heat sufficient to dry the powder below its average normal air-dry state,then abnormal variationsin the explosive 0 force take place, varying in intensity according to the dryness, and up to complete dryness of the powder, in which state also expel nenthas proved powders containing trinitro cellulose to beexceedingly dangerous.

The powder manufactured by my process has the further advantage that if it should by any chance take'up] an excess of moisture over the average-normal flied y quantity, then,

if such powder be subjected to warmth or heat rco to drive off such excess of moisture, (even if the moisture be absolutely removed,) the strain upon the weapon set up by such dry powder is never more than that of ordinary black gunpowder in its ordinary shooting state, and the powder manufactured by my process exerts in its average normal or air-dry state a strainupon the weapon much less than that fro ordinary gunpowder.

- the varyingamount of moisture in the powder do not exert any marked or dangerous effect in its use; and generally inthe use ofa powder,

prepared by my process there is a more gradual pressure during combustion in the gun than in the case of a powder yielding the same projecting force, but containing trinitrocellulose in important quantities, as in such powders nowinthe market.- g

In carrying my invention i-njt-oefi'eet the nitro compound mixed vwith sufiticient water.

to be uninflam mabl esuch, and for example, as dinitro-cellulose is first mixed,'by.appropriate means,with oxidizing agents,;as'nitrate of potassium or of barium, and-when deemed advisable, according to'theexact use tolwhich the explosive is tobe put, with other mate-- rials-such, for instance, as hydro-oell-ulose,

wood-flour, torrefied starch, lamp-black, or charcoal. As an example, for military firearms, I may mention fifty parts, by'weight, of nitrocellulose, forty parts of nitrate of potassium, and ten parts of torrefied starch or lamp-black. As an example,for sporting "and shot guns, I may mention fifty parts of 'flnitrocellulose, twenty-five parts of nitrateibfiba rium,'twenty-two parts of nitrate potassium,

and three parts of torrefied starch or lampblaek. The nitro compound, eitherfipure orin admixture with substances, suchasare, mentioned above,- is then brought into the form of small g'ranules,by well-knownmeans, or.is molded by more or less compression into suitable forms-such, for instance, as eylin de-rs, prisms, or cubes. The granular powder,

hereinafter spoken of as the grains or the cylz. -inders, prisms, or'cubes, hereinafter described as the blocks, are deprived of their moisture,

by heat 'or otherwise, and are then fit to un dergo the treatment about to be described..f A

weighted quantity of the grains or blocks-is taken, and a preliminary experiment is made to determine what quantity of any of the solvents or mixed solvents of camphor is required to saturate the grains or blocks without these being unduly wet. The solvent or mixed solvents of camphor chosen are such as evaporate below 100 centigra'de, and neithenper se nor with the camphor in solution exert anymaterial gelatinizing,solvent,or detrimental action upon the explosive compound. In practice light petroleum or benzoline is found both an economical and convenient solvent for the camphor. affine-oil, rosin-oil, or easily-fusible fatty or resinous matters-ma-y also be added to the grains or blocks, as I have found that Such" materials aid in eifecting the desired slowing action. This is easily and conveniently effeeted by introducing the same into the cam phorsolution, so that whenhthe volatile solvcut or solvents are driven 011' the non-volatile oily or fatty matter remains behind in the grains or blocks, together; with the eamphor. Havingdiscovered the proper saturating proportions of the solventor mixed solvents of camphor in relation to the grains or blocks, a solution bf camphor is prepar'ed,of: a strength such that the grains or blocks when saturated with the solution may contain that quantity of. .camphor which is found by experiment to effect the production, as may be'desired, of an explosive more or less hard and, respectively, of a more or less slowly-burning nature. In

Various non-volatile oils-.such as parpractice it is fouudathat a proportion of one part, byweight, of camphor and five parts, by weight, of the solvent to ten parts, by weight, of the nitro compound or mixture gives good results; but it is to be clearly understood that the proportion is not limited to thisor any otherherein expressed or uuexpresse'd; or insteadiof the one part of camphor I may use, say, 0.5 .part of camphor, five partsof thesolvent, a'ndfO.5 part of phenol to ten parts, by

weight,.0f the nitro compound or mixture. Having prepared an appropriate solution of eamphor, the grains or blocks are saturated. therewith, sufiicient time being allowed forthe solution to thoroughly permeate every part of the nitro compound. The grains or blocks intima e ac ion ,or etralion in the pores, 1

especially with large blocks,I may exhaust the air more or less from the space abovethe saturating-liquid contained inacl'osed vessel and from the pores of the niti'o compound placed in that space before imui'ersidm-and ad mit the airagain after immersion, so as to use l the air-pressure to complete the saturation, suitable means being provided for lowering and raising the basket into and out of the l'rq- 'uid while in the saturating vessel. I then allow the excess of liquid adhering to the grains or blocks to drain oif before proceeding with the next process-via, that of evaporating 011' the volatile solvent and collecting the same for repeated use. i

It is to be clearlyunders tood that I do no bind myself to the employment of anyspecial v form of apparatus for effecting the evaporation and condensation of the volatile solvent; but in practice I have found it' convenient to employ a circular pan heatedfrom without by steam or hot water, and provided with a me chanical stirrer revolving concentrically or otherwise. Fitting closely to the circular pan is a dome of about the same diameter and'section as the lower vpan., This dome has an aperture at its highest part, by which the vapors of the volatile solvent pass into an ordinary still-head which may surmount and form part of the dr e, and thence to an ordinary con.- denser. The volatile solvent is driven off at the lowest possible temperature, and leaves the camphor disseminated in the solid or crystalline form throughout the grainsor blocks,

, higher than 100 centigrade. At this tem-' perature the camphor exerts a remarkable action upon the nitrocellulose, and the grains or blocks which at first were easily pliable are by this treatment rendered very hard,or of any required hardness, according to the percent age of camphor used in the solution. The

camphor may now be driven out of the grains or blocks by sublimation or evaporation un-.

der ordinary or reduced pressures, or in a current of steam or air or other gas, or it may be washed out by treating the grains or blocks with any appropriate solvent or solvents of camphor.

When the apparatus mentioned above is used to effect the driving off of the volatile solvent, the whole of the operations-via, mixing the grains or blocks with the solution of camphor, with or without the aforesaid exhaustion and readmission of air, driving off and condensing the volatile solvent, heating the grains or blocks containing solid-camphor permeated through their mass, and, lastly, the driving off by heat and collecting the camphor driven ofl'may be conveniently carried out in the sameapparatus.

When the camphor is to be removed from tlreblocks'orgrains by washing, a rapidpropetroleum-and then expel the petroleum'or cess is to saturate the grains or blocks with some volatile sol vent of camphor-such aslight other solvent with the camphor in solution by means of centrifugal force. With this object a centrifugal hydro-extractor, so constructed as to allow of as little air as possible passing 1 through the grains or blocks, may be advantageously employed. Any'slight residue 'of the volatile solvent left in the'grains or'blocks alter the centrifugal process is expelled by 'means of heat. By varying the proportion of the camphor the action of the same upon the nitrocellulose at and up to the temperature scribed.

named is such as to afford an exactly-adjustable means of obtaining an explosive having any desired-action or intensity, either sudden or more gradual, or even extremelygradual. It is to be distinctly understood that these results-are obtained not by the presence of cam fphor in large or small quantitiesjin the finished explosive, (from which most, if not all, the camphor has, on the contrary, been elimi nated, as hereinbefore described,) but by a re-. markable gelatinizing and, perhaps, some other action exerted by the camphor upon the nitro: cellulose when these are heated together at varying temperatures up to 100 centigrade, whereby the hardness and density of the explosive may beregulated at will by the proportion of camphor used.

Where conditions'are such that an explosive isrequired of greater density than that ob.-

tained by the foregoing processes in the case of I the grains treated as described, these are subjected en masse to a great pressure, so that a cake is formed. This cake is, however, easily brokenup, practically, into the original grains, and these are found to possess a higher density, and have an angular or more or less flattened form, conducive t0 rapidity of ignition. Instead of compressing the grains en masse,

the grains may be passed between-accurately turned rollers, so adjusted as to exert a very considerable degree of pressure upon .them,

having the effect, of increasing-thedensity and givinga more orless angular or flattened form; or the hard approximately spherical granules may also, after treatment by the camphor process, be molded by compression into various forms-s uch'as cylinders, prisms, cubes, or spheres. In this way small cylinders, for instance, containing the exact charge of powder for use in firearms, may be manufactured. Instead of applying the compression to the hardened granules freed from camphor, as above, the granules freed from volatile solvent but'still containing camphor permeating the mass, may be compressed or molded by compression. The formssu.ch as cylinders, prisms, cubes, or spheresobtained by such compression are then heated at temperatures not exceeding centigrade until the action of the camphor is complete and the camphor IOO is finally removed,as far as practicabla elther by sublimation or by"'being"washedout by means of an appropriate solveu t, as before detreatment with "a solution of camphor in a volatile liqnidnot a solvent of nitrocellulose, and-"expelling the solvent at a low tempera} ture,thensubjecting the camphorated nitro cellulose to atemperature sufiicientlyhighfor the camphor to change the mechanical": e

of the nitr0-c'e1lul0se,and finally expelling'the tmperatnrathen slihjepting the eamphorized ip c'amphor, all substantially as described. material to a temperatnre sufficiently high for 2. The process, substantially as described, I the camphor t o changethfe mechanical state of for the preparation of explosives, which conthe dinitro-eellulose, and finally expelling th sists inAincorporating dinitr0-cellnl0se with ean'iphor, all su bstantiallyas described, barinm and potassium nitrates and carbon, DAMID JOHNSON. treating the mixture wilh a solntionof camphor in a volatileliqnid not a solvent of dinitro-cellnlose, evaporating the solvent at a low Vitncsses:

(1 A, JENSEN,

WALTER J. SKER N 

